Ankle

Abstract

Traumatic injuries of the ankle joint are very common and usually result from “taking a wrong step” either in sport or in everyday life. The body’s reaction is standard: pain, swelling, and impaired function. Unfortunately, these reactions may not tell the whole story; in fact, they can even be misleading. A complete rupture of the joint capsule and one or more of the ligaments may result in less pain than a distortion because the intra-articular effusion or bleeding is not contained in the joint but has ways to diffuse into the surrounding soft tissue, thus placing less stress on the joint capsule. On the other hand, the rupture of a small capsular artery may produce a large swelling despite only minor trauma. Since the clinical appearance does not allow a diagnosis to be established with sufficient certainty, the imaging techniques are very important. While there is considerable debate among orthopedic and trauma surgeons over when to operate on ligamental and capsular injuries and when to employ conservative treatment, there is little disagreement that most bone lesions require a surgical approach. The goals of the radiological examination can, therefore, be defined as follows:

• 1. To prove the existence or absence of osseous lesions, i.e., the “visible joint”

• 2. To determine the degree of ligamental injury, i.e., the “invisible joint”

The visible joint is for the most part accurately displayed by radiographs in two or three projections and, if necessary, by conventional or computed tomography. The invisible joint is depicted by arthrography and/or magnetic resonance imaging (MRI), while stress examinations give a good idea of the clinically important function of the invisible joint.